Troubleshooting

Potential problem

Voltage not releasing.

Possible reason

Faulty switch.

Solution

Replace switch.

Potential problem

Rotor and armature locked together.

Possible reason

The clutch has been severely galled and has locked up. (Galling is the condition whereby a piece of metal is trapped between the armature and the rotor and melts due to high pressure and heat, spot welding the surfaces together.)

Solution

If rotor and armature cannot be separated, replace the clutch. If they do separate, follow burnishing procedure.

Potential problem

Pulley bearing locked.

Possible reason

Bearing lost grease due to seal problem, temperature or water contamination.

Solution

Replace clutch.

Potential problem

No voltage going to the clutch.

Possible reason

Wiring connector not seated properly.
No voltage or low voltage coming from the battery.
Defective charging system.
Lead wire cut or broken internally.
Fuse blown.
Defective switch operating clutch.

Solution

Pull apart and re-seat connector.
Check with voltmeter, battery should be 8-16 volts. (Assuming 12 volt battery.)
Fix charging system.
Fix or replace lead wire. If destroyed, replace clutch.
Replace fuse.
Replace the switch.

Potential problem

If voltage is going to the clutch, but the clutch will still not engage.

Possible reason

Coil open or shorted.
Check coil voltage to make sure it is compatible with the voltage coming in. (If voltage is too high, this could cause the coil to burn out.)
Burnt out coil caused by frictional contact (rotor strike). If so, coil will be discolored, can be cracked, burnt or epoxy can be melted.

Solution

Check coil with ohmmeter. A range close to 3 to 4 ohms should be present at an ambient coil temperature of 70F. Replace coil.
Change battery or coil to meet your requirement.
Replace coil.

Potential problem

Clutch engages, but load will not engage.

Possible reason

Rivets or springs broken.
Key missing.
Armature could be warped because of heat due to slippage. This means it will pull in, but will slip when a load is supplied. Clutch should show signs of heat.

Solution

Replace clutch.
Put in key.
Replace clutch and determine why it slipped.

Potential problem

Low voltage going into the clutch.

Possible reason

Defective battery.
Lead wire cut which could be intermittently grounding out the lead wire causing the clutch to turn on and off or not to give full voltage.

Solution

Check with voltmeter, battery should be 8-16 volts. (Assuming 12 volt battery.)
Fix or replace lead wire.

Potential problem

Erratic engagement.

Possible reason

If lead wire is kinked or pinched and the break is internal, the clutch operation may show up as being erratic engagement.

Solution

Fix or replace lead wire.

Potential problem

Clutch is contaminated.

Possible reason

Oil or other lubricant has been sprayed on the clutch surface. Sometimes this shows up after the clutch is disassembled. Physical evidence is either burnt oil or a greasy metallic surface showing oil still present.

Solution

Clean off surfaces with solvent and re-burnish. Replace the clutch if damage is severe enough.

Potential problem

Clutch overloaded.

Possible reason

Output torque required is greater than what the clutch can handle. If input torque going into clutch is greater than the output torque required, the clutch will slip. If it slips too long, the clutch surfaces will be galled.

Solution

Size clutch correctly for the application. Replace clutch.

Potential problem

Output stalled.

Possible reason

If output is stalled, clutch could slip to the point where it will burn up and destroy either bearings or the field.

Solution

Replace clutch.

Potential problem

If voltage is going to the clutch, but the clutch will still not engage.

Possible reason

Coil open or shorted.

Solution

Check coil with ohmmeter. A range close to 3 to 4 ohms should be present at an ambient coil temperature of 70\uffffF. Replace coil.

Potential problem

Clutch not burnished.

Possible reason

If full torque is required immediately and clutch is not burnished, it will slip and could become galled.

Solution

Try to re-burnish clutch. If slipping is to severe, clutch will have to be replaced.

Potential problem

If clutch is able to move on the shaft.

Possible reason

Check center bolt and washer to make sure it is tight. If it is tight, make sure that the shaft is not too long. Clutch shaft should end before the end of the clutch to allow some deflection in the center bolt and washer to keep clutch on tightly.

Solution

Retighten center bolt or change spacer or shaft length.

Potential problem

Noise from pulley bearing.

Possible reason

Check if bearing feels rough. Check belt load to make sure pulley and bearings are not over loaded.
High temperature can be caused by either operating environment or due to slippage. If slippage, clutch should be discolored. Refer to slippage section for potential reasons.

Solution

Reduce belt load.
Reduce the heat or eliminate slippage.

Potential problem

Pinging or scraping noise noticed when clutch is disengaged.

Possible reason

Air gap too close.
Surface is heavily galled.

Solution

Increase air gap.
Re-burnish the clutch.

Potential problem

Noise from field bearing.

Possible reason

Check to see if the clutch is discolored to see if it shows signs of slippage.
Check for damage to both the outer race and inner race of the bearing. Make sure key is not too tight forcing pressure on the inner race . In the outer race area, check for marks or damage that could have caused the clearances to close up.
Check temperature of shaft where clutch is mounted to verify that it is under 300°.
Check torque tab or backing plate to make sure that there is freedom of movement of 1/16 of an inch axially and radially. Check to see if any marks are evident that would indicate axial forces applied.

Solution

Refer to slippage section.
Replace clutch.
Reduce reason for the high temperature overloading on the engine.
Loosen torque tab to make sure it has freedom of movement both axially and radially.